how to define RMAN retention policy time?

Many a times, I heard DBA’s complaining about RMAN retention policy through which they face some problems during restore or recovery.

For example a friend posted that his retention policy is set to recovery window of 90 days, but when tried to restore the database to 30 days back date, RMAN saying recovery till that time is not possible. he wondered why this cannot be done if he has retention of 90 days.

Here is the answer for the same….

we all know that RMAN will store backup metadata in control file’s reusable location if recovery catalog is not configured. Generally this information will be stored for 7 days and can be changed by modifying CONTROL_FILE_RECORD_KEEP_TIME parameter.

whenever we define retention policy of RMAN either to recovery window or redundancy to some X value, we need to remember that RMAN still follow the value defined for CONTROL_FILE_RECOD_KEEP_TIME. That means, if recovery window is set to 30 days, but the above parameter is set to 7 days (default), you cannot recover beyond 7 days… which is very unfortunate…

Right ! so lets see what can be done for this?

we need to define CONTROL_FILE_RECORD_KEEP_TIME always a higher value than what we set for retention policy. As per the formula, it should be

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This entry was posted on July 11, 2011 at 7:29 PM and is filed under RMAN.
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Sohailsaid

Sohailsaid

Hi Pawan, Awesome information i got it from you, but still i have some more doubts about rman. As u said that windows or any platform default retention policy 90 days, where to check this and how? Especially iam using linux, so in linux envirement, what is the default retention policy. Awaiting for your response ……………

Sumit Gargsaid

Don’t you think that control file will auto grow in case you mentioned rather than overwritting that.It should auto grow till OS limit permits but yes if control file can’t grow because of os size limit, that above case will happen ?

shahid ahmedsaid

Firstly i would like to thanks for this post. The description is very useful and in simple and in clear word.
I Don’t tested on higher version but in oracle 9i the parameter is
CONTROL_FILE_RECORD_KEEP_TIME

Please verify if i am correct please add it because your post is useful for all of us.